I recently was forwarded an article on The Ring Theory. It's a simple way to be sure your comments to a person having tough times are helpful instead of hurtful. So that you are actually supportive (which is usually the intent, right?) instead of accidentally "dumping" on the other person with your own emotional reaction to his or her hardship - in a sense further burdening that person.
I think about the times I've had some heavy stuff happening in my life; some people knew how to listen and be empathetic. Others gave well-intentioned, but unsolicited, advice that always made me feel worse.
Another really good reminder that comes from the Ring Theory is that those closest to the "aggrieved or afflicted" also just needs support - not advice or your inner thoughts - those are to share with someone else further out the rings from you.